I've been wondering and haven't seen it discussed here (it's certainly possible I may have missed it) but what do you guys think they meant by "TONY STARK WILL RETURN" at the end of the credits and even after the Banner scene? I took that as a "RDJ or no RDJ, don't worry we'll have a Tony Stark somewhere" kind of vibe.

I took it to mean that we may not necessarily see Iron Man in Avengers 2 but definitely Tony Stark. Doubtful that will be the actual case.